Auditory Tube

Question 1

What are the components of the auditory system?

Answer 1

Outer ear -air
Middle ear - air
Inner ear - fluid
Central Auditory Pathways

Question 2

What are the different parts of the outer ear?

Answer 2

Channel the sounds in towards the auditory meatus (helical folds)

Question 3

What are the smallest bones in the body?

Answer 3

the oscicles
Formed adult size at birth

Question 4

Ear drum is in 2 parts

Answer 4

floppy one much more vulnerable

Question 5

What is in the middle ear?

Question 6

What is the attic?

Answer 6

In the middle ear

Question 7

Which nerve travels across the back of the eardrum?

Answer 7

Facial nerve
Really risky in surgery

Question 8

What is the role of the middle ear?

Question 9

How does the mechanical energy (sound) get converted to electrical energy?

Question 10

What do muscles do in the middle ear?

Answer 10

Protect the inner ear from acoustic trauma
Stapedius is stimulated acoustically so relies on reflex arc so can’t protect against rly quick sounds

Question 11

What are the muscles in the middle ear?

Answer 11

tensor tympani - stabilises tympanic membrane
stapedius - stabilises stades

Question 12

Where is the vestibulocochlear apparatus?

Answer 12

the inner ear

Question 13

What is in the vestibulocochlear apparatus?

Answer 13

cochlear
labyrinth
innervation

Question 14

3 sections of the cochlear?

Question 15

What are the cochlear fluids?

Answer 15

2 ionic fluids
Endolymph (scala media)
high K+
Perilymph (scala vestibuli/ typani)
Like ECF and CSF
Na+ rich

Question 16

Why are you likely to have impacted hearing with ion channel abnormalities?

Answer 16

ionic fluids in the cochlear

Question 17

Oval window

Answer 17

window to scala vestibuli

Question 18

What does the helicotremaa do?

Answer 18

allows wave movement in the cochlear, as it keeps the system open (it is a small hole at the end of the cochlea)
pressure moves through - moves the basilar membrane, it separaes the scala tympani and the scala media

Question 19

How does movement of the basilar membrane cause sound?

Answer 19

stiff and narro - responds best to high frequency sounds w at base
broad and floppy at apex - responds best to low frequency sounds
different parts of the membrane move in response to different pitch - middle part is middle pitch, start is high pitch

Question 20

Where is the organ of corti?

Answer 20

basilar membrane
inner hair cells attach tectorial to

Question 21

difference between basilar and tectorial membrane?

Answer 21

tectorial is fixed

Question 22

basilar membrane on histological level

Answer 22

inner hair cells move as basilar membrane is displaced, base is attached
inner hair cells moving causes activation of the auditory nerve - this activates the central auditory pathway

Question 23

how do outer hair cells fine tune sound?

Answer 23

selectively activate the inner hair cells

Question 24

How do movement of the sterocillia depolarise?

Question 25

What is the pathway from the neurone to the brain?

Question 26

What is sound localisation?

Answer 26

time difference of sound arriving
intensity difference - one side is quieter
so hearing in one ear - lose sound localisation and differentiation - overlap of sounds e.g. in cafe are hard

Question 27

how does sound localisation work in the brainstem?

Answer 27

crossing over point - they don’t meet in the middle, one has